1. Field of the Invention
The invention is primarily concerned with the application of designs and other graphics to smooth substrates and is particularly concerned with forming graphics on glass panes, which graphics appear to have been etched or sand-blasted into the glass.
2. Description of the Related Art
The company to which this application is assigned manufactures vinyl films which can be applied to glass panes to form graphics that appear to have been etched or sand-blasted into the glass at a fraction of the cost of actual etching or sand blasting. These vinyl films, typically plasticized poly(vinyl chloride), are marketed as Scotchcal.TM. Series 7725 special effects films. Among these, Scotchcal.TM. 7725-314 Dusted Crystal Film gives the appearance of etched glass, and Scotchcal.TM. 7725-324 Frosted Crystal Film gives the decorative appearance of sand-blasted glass. Each of these is translucent white. The ability to form such graphics makes it economically feasible to warn persons, in a visually attractive manner, not to walk into a large glass panel that otherwise might be mistaken for a door. Both decorations and messages (below collectively called "graphics") may be used in any such warning.
Each of these special effects vinyl films bears a layer of aggressive pressure-sensitive adhesive and a low-adhesion carrier web that protects the adhesive. The pressure-sensitive adhesive is selected to form strong bonds to glass.
In use, graphics are cut into the special effects vinyl film without cutting through the carrier web, and the adhesive-bearing weed is peeled from the carrier web and discarded. A piece of paper that bears a removable pressure-sensitive adhesive (here called an "application tape") is temporarily adhered by that adhesive to the exposed faces of the graphics. The low-adhesion carrier web is removed to expose remaining areas of aggressive pressure-sensitive adhesive. Both the adhesive side of the paper-covered graphics and a glass panel are wet with a solution of non-creamy dish detergent and rubbing alcohol in water. The wet, aggressive pressure-sensitive adhesive covering the graphics is pressed against the wet panel, and the detergent, alcohol, and water solution is allowed to evaporate until the graphics have become bonded to the panel. The application tape is then peeled off to expose the graphics.
The detergent, alcohol and water solution has two functions. First, when using a squeegee, the solution aids in eliminating air from the interface between the graphics and the glass panel. Second, the solution permits the graphics to be repositioned to a desired location, based on measurements made before the solution is applied. Such measurements are necessary because the graphics cannot be seen through the sheet of paper. Because the difficulty of making and using those measurements, the special effects vinyl films have been marketed primarily for application by skilled artisans.
In addition to being used to form graphics on glass panels to achieve an etched or sand-blasted appearance, special effects vinyl films are applied in the same manner to form other graphics on various substrates such as the side of a truck or other automotive vehicle.
A number of additional commercial products are used to apply graphics to glass panels and to other substrates. In several of these, the outer sheet that covers the graphics-forming layer is transparent or translucent, e.g., a polypropylene film. Illustrative is SCTT-10 application tape manufactured by the company to which this application is assigned.